Heretofore, many efforts have been made to develop an effective and inexpensive litter for animals, especially household pets, particularly cats. Thus it has been disclosed in various patents to use alone or in various combinations urine sorptive materials, odor-inhibiting or control chemicals or materials, antioxidants, microbial inhibitors, surfactants, dyes, antistatic agents, flame retardants, binders, encapsulants, neutralizing agents, weighting or density control agents, and other materials.
Starches, modified starches, and starch-containing materials have been disclosed for use as binders in animal litter products. Brewer U.S. Pat. No. 3,921,581 indicates that pregelatinized starches can function as a binder and water-sensitive disintegrant in a solid excipient containing a solid carrier, i.e., finely subdivided cellulosic solids or minerals, and that the pregelatinized starches do not impart any adhesiveness to the powder residue after disintegration of the particles. Fry et al. U.S. Pat. No. 3,923,005 discloses an animal litter wherein dried alfalfa is admixed with a starch-containing material, and the admixture is treated by a conventional extrusion cooking process to yield an expanded low density pelletized product. This patent indicates that the gelatinized starch binder gives the pellets an improved stability when wet, and substantially prevents structural decomposition of the finished product on contact with liquid animal wastes. The product pellets are substantially free from clumping when wet and absorb without physical expansion. Brewer U.S. Pat. No. 4,206,718 discloses a mixture of ground alfalfa with a gelatinizable carbohydrate such as flour in the weight ratio of 75:25 to 25:75 which is heated under steam pressure to gelatinize the carbohydrates and bind the particles together. Thereafter the bound together particles are expanded and then pelletized and dried. Ducharme et al. U.S. Pat. No. 4,727,824 provides absorbent compositions comprising a major amount of a cellulosic hull material, alone or in admixture with a cellulosic plant pulp, and a minor amount (generally 2-25%) of a carbohydrate or protein binder. The carbohydrate binder can be any ground or refined plant product such as a flour or starch from plant sources. Brewer U.S. Pat. No. 3,789,797 discloses the use of modified starches as a binder in the preparation of litter pellets containing alfalfa and bentonite. Carlberg U.S. Pat. No. 4,157,696 discloses the use of starch as a pelletizing aid in a liquid absorbent. Pris et al. U.S. Pat. No. 4,258,660 discloses the use of corn starch as a binder in a litter composition. Litzinger U.S. Pat. No. 4,311,115 discloses the use of starch as a binder in a liquid absorbing composition. Kok U.S. Pat. No. 4,374,794 discloses the use of starch as a binder to obtain pellets having a good firmness and dimensional stability. Harke et al. U.S. Pat. No. 4,560,527 discloses a cat litter comprising agglomerated cellulosic particles in which starch may be present as a binder. Crampton et al. U.S. Pat. No. 4,591,581 discloses absorbent clay mineral particles containing 0.2% to 5% by weight of a water dispersible colloid, which may be starch. Lojek et al. U.S. Pat. No. 4,676,196 discloses the use of 1-3% of a starch binder in a dried agglomerated absorbent material.
Fisher U.S. Pat. No. 3,916,831 discloses the use of popped popcorn as an animal litter.
In the last 10 years or so there has developed a new type of cat litter which "captures" the urine in a "ball" or "clump" of litter which can be scooped from the nonwetted litter for easy removal. These so-called "clumping" or "scoopable" litters have been based on one or more clays. Although these clumping litters have been vast improvement in eliminating the waste before it generates obnoxious odors, these clumping litters still possess one or more undesirable properties or characteristics. These include: high bulk density; poor clumping (poor cohesiveness of the wetted litter); dustiness; excessive wicking or sorption of the urine into the bulk of the litter before the wetted ball of litter is removed; friability of the clump of litter if it is not removed while substantially wet; and nonbiodegradability of the litter. Certain of the scoopable litters are said to be flushable down a commode provided that it does not empty into a septic tank. However, although the clump of litter breaks up upon placement in the commode, the litter contains clays and other minerals which are not dispersed and thus which may settle out within the conduit carrying the waste from the commode. This may result in blockage of the conduit, and can be especially troublesome in places having a high animal concentration, such as apartment complexes and the like. The following U.S. patents all disclose various clumping or scoopable cat litters: U.S. Pat. Nos. 4,685,420 (Stuart); 5,000,115 (Hughes); 5,014,650 (Sowle et al.); 5,058,533 (Nelson); 5,094,189 (Aylen).
Thus there is still a need for a superior litter which eliminates the odors associated with animal waste, and particularly for such a litter which is dust free and biodegradable such that it can be flushed into any waste system, including those which empty into septic tanks.
It is an object of this invention to provide a dust free, biodegradable clumping sorbent having sufficient cohesiveness when wetted with an aqueous liquid, such as urine, to be easily separated from the nonwetted sorbent particles, the sorbent being a modified natural product having a bulk density in the range from about 500 kg/m.sup.3 to about 900 kg/m.sup.3, a reducing sugar content from about 0.5 to about 4% by weight, a cold water solubles content from about 40% to about 90% by weight, and a particle size distribution such that at least 75% of the particles thereof are from about 250 microns to about 2000 microns.
It is another object of this invention to provide an improved method for agglomerating urine to facilitate removal of the urine from a litter box, wherein the urine contacts a litter sorbent which is cohesive when wetted and which agglomerates the urine into a lump of wetted litter, the improved method comprising using as the litter a modified natural product having a bulk density in the range from about 500 kg/m.sup.3 to about 900 kg/m.sup.3, a reducing sugar content from about 0.5 to about 4% by weight, and a cold water solubles content from about 40% to about 90% by weight.
These and other objects of the invention will be readily apparent to one skilled in the art as the description thereof proceeds.
While the invention is susceptible of various modifications and alternative forms, specific embodiments thereof will hereinafter be described in detail and shown by way of example. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the invention is to cover all modifications and alternatives falling within the spirit and scope of the invention as expressed in the appended claims.
The compositions can comprise, consist essentially of, or consist of the stated materials. The method can comprise, consist essentially of, or consist of the stated steps with the stated materials.